Automatic switch-bank cleaning means



United States Patent O 3,465,376 AUTOMATIC SWITCH-BANK CLEANING MEANS George H. Smith, 3360-D Norton Ave., Lynwood, Calif. 90262, and Leonard 0. Salmon, Lynwood, Calif. (16230 Cornuta Ave., Bellflower, Calif. 90706) Filed Feb. 19, 1968, Ser. No. 706,571 Int. Cl. A46b 11/04 U.S. Cl. 15-104.92 6 Claims ABSTRACT OF THE DISCLOSURE Cleaning means comprising an applicator with a wick that receives cleaner uid and is provided with a set of tufts of bristles directed angularly upwardly and in the path of movement of intermittently advanced contact brushes of a rotary telephone-central switch having bank terminals engaging said brushes and which are both cleaned by said bristles and are moistened by cleaner iluid wetting said bristles and drawn from said wick through orices of pinpoint size, a cleaner fluid holder xedly mounting the applicator by means of a tube that conducts uid to the Wick and is adapted to be mounted adjacent the switch to service the switch brushes automatically as the same are intermittently advanced.

Background of the invention Telephone central rotary switches, characteristically, have circumferentially arranged banks of contacts that are intermittently engaged by rotatively advanced contact brushes in the normal operation of central office equipment. Such switch banks may become dirty or tarnished due to formation of oxides, sulphides and like trouble-causing lms. Foreign matter, as dust and dirt and/ or such contact-impairing films, may cause switching failures, wrong numbers, noise, cross talk and other service-affecting troubles. Accordingly, an object of the present invention is to provide means that automatically and continuously, as demanded by the operation rate of the switches, keeps the banks of contacts thereof free of such lms, dust and dirt, thereby to maintain them in effective operating order at all times.

Another object of the invention is to provide means of the character referred to that applies cleaning fluid to such banks of contacts through the medium of intermittently advanced contact brushes or wipers which are cleaned of dirt that they pick up from the banks of contacts and are then wetted by such uid for transport and application to the banks of contacts as the brushes advance to operative engagement with the contacts.

A further object of the invention is to provide means, as above characterized, in which the brushes draw such -iluid from the bristles of an applicator unit which receive the fluid by gravitational ow from a supply thereof and then by capillary attraction.

A still further object of the invention is to provide switch-bank cleaning means, of the character above re ferred to, in which the movement of fluid to the bristles, while continuous, cannot over-feed and cause the brushes to become unduly drenched, since the transfer of uid from the bristles to the contact brushes by capillary attraction occurs only during the movement of the latter through the bristles; at all other times, the feed flow from the supply to the bristles is arrested and awaits the next engagement of the brushes with the bristles, as hereinabove contemplated.

This invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

Patented Sept. 9, 1969 ICC Summary of the invention The present switch-bank cleaning means comprises, generally, a cleaning fluid applicator 10 for operative engagement with the intermittently advanced contact brushes or wipers B of a rotary switch S provided with banks of contacts C, a tube 11 connected to the applicator for conducting cleaning fluid thereto, and a xedly mounted cleaning fluid holder 12 for providing said tube with a gravity iiow of such uid.

Brief description of the drawing In the drawing, like reference characters designate similar parts in the several views.

FIG. 1 is a side view, partly in vertical section, of switch-bank cleaning means according to the present invention and shown in operative relationship to a rotary switch and to the contact brushes thereof.

FIG. 2 is a front elevational view of said means.

FIG. 3 is a broken and enlarged top view, partly in section on the line 3 3 of FIG. 4 of a iluid applicator shown in FIGS. 1 and 2.

FIG. 4 is a cross-sectional view as taken on the line 4-4 of FIG. 3.

FIG. 5 is a further enlarged and fragmentary sectional view of a detail of said applicator.

Description of the preferred embodiment The rotary switch S typically comprises a plurality of switch banks, each having a plurality of circumferentially arranged contacts C, and a plurality of contact brushes or wipers B mounted on an axis 6 that is on the center around which the contacts C are arranged. Said brushes B, during the normal operation of telephone central exchange equipment, are rotationally and intermittently advanced, at varying time intervals, to effect electrical engagement with one of the contacts C of the switch, according to the numbers dialed. It will be understood that such switches may have varying numbers of switch banks C and corresponding numbers of brushes B, to a maximum of ten, the same being centered as on a center line 7 (FIG. 2) on which the applicator 10 is also centered so it may have operative engagement with the brushes B as they are advanced, in the direction of the arrow 8 of FIG. l, to make contact with one of the contacts C.

The applicator 10 is shown as having an elongated body 15, preferably of a plastic material that, advantageously, may be transparent. A hollow or cavity 16 in said body houses a wick 17 which may comprise a wad of absorbent material, such as cotton. A plastic wall 18 of said body encloses the wick after the latter has been placed in the hollow 16, and is permanently fused to the main portion of the body.

Cleaning iluid is gravitationally conducted to the wick 17 by the tube 11 that is xedly connected to the body 15 as by a suitable threaded engagement of the body and tube, by `a lock nut 19, and a leak-sealing washer 20 between the body and the tube. While the tube 11 is shown as entering through an upper wall of the body 15, the same may be connected to a rear wall or one of the end walls provided, however, the body is retained in the position indicated in the drawing.

As best shown in FIG. 4, a row of tufts of bristles 21 extends from and is arranged longitudinally of the body wall 18. For the accommodation of all the brushes B of a rotary switch S centered on the line 7, said row may comprise fifteen tufts between which the present maximum of fourteen brushes may be passed during movement of said brushes in the arcuate path of arrow 8. Additional rows of tufts of bristles are provided, one or more rows 22 on the side of the row 21 from which the brushes B approach, and one or more rows 23 on the opposite side of row 21. The drawing shows sixty tufts of bristles arranged in four rows and it is between the tufts of said rows that the brush B moves in a transverse arc to pass between two tufts of each row 22 to be wiped first by the bristles of said tufts then between two tufts of row 21 and finally between two tufts of row 23.

As shown in FIGS. 3, 4 and 5, a conically flared opening 24 has its large end open to the hollow 16 of the body and the wick 17 therein, and its smaller end 25 in register only with each of the tufts 21. Said end -is of pinpoint size so that fluid entering said openings 24 will, by capillary attraction, be drawn along the bristles of the row of tufts 21. As a consequence, said row is a fluidwetted row, while the rows 22 and 23 have dry bristles.

It will be clear from the foregoing that, whether one or more rows of bristles 22 is provided, the same will wipe particles from the brushes B which may have been picked up from a contact or contacts C as the brushes advance; that the bristles of row 21 will transfer the fluid that wets them to the brushes, as they advance; and, finally, that the bristles of row or rows 23 will remove excess fluid from the brushes as they advance to electrical wiping Contact with the switch contacts C. Upon such removal of fluid from the row 21, the mentioned capillary attraction will become effective to re-wet the brisi tles, as explained.

The fluid holder 12 may be of a size to store as much as a years supply of fluid and advantageously comprises a transparent container 26 so visual inspection will show the level of fluid therein, an air-tight stopper 27 that is removed while fluid is added, and a filter or screen 28 to remove impurities from the fluid being supplied. Due to the air-tight t of the stopper, the gravity flow from the container 28 to the tube 11 is slowed, as is the capillary-induced movement of the fluid to the bristles. When the brushes B are moving through the bristles of tufts 21, a drawing force on the fluid combines with the capillary force to effect a fluid replacement on the bristles for the fluid thus removed. Until a brush B again draws fluid, as described, the flow of fluid ceases.

It will be evident that such control of fluid feed follows from the fact that the bristles 21 have an upwardly directed disposition, in this case at an upward angle. Thus, the capillary attraction of the fluid causes the same to be drawn in an upward direction, preventing undue flooding. Also, the gravitational flow from tube 11 fills the applicator body and saturates the wick 17, but the elevated relation of the bristles 21 with respect to the wick keeps the feed from the wick to one that is carried out by capillary attraction.

The container 26 may have any non-round shape so the same has a fixed position when clamped in place on a wall 29 by a clamp 30, thereby :insuring proper positioning of the applicator.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. Means for cleaning and applying cleaning fluid to the intermittently advanced contact brushes of a rotary switch for transfer of said fluid to the contacts of said switch, comprising an applicator provided with:

(a) an elongated body having a hollow therein with a wick occupying said hollow,

(b) an inlet connected to said body to gravitationally conduct cleaning fluid to said wick,

(c) a plurality of tufts of bristles extending from a wall of said body in a direction at least partly upwardly, said tufts of bristles being arranged in plural rows extending lengthwise of said wall,

(d) a plurality of constricted openings in said wall open to the hollow of the body and receiving fluid from the wick in said body, one such opening being provided in register with each tuft of bristles of one row thereof,ythe latter bristles, by capillary attraction, drawing fluid from said openings and becoming wetted thereby, and

(e) at least one of said plural rows comprising a row of tufts of dry bristles arranged along each side of the row of tufts of wetted bristles,

(f) said contact brushes, when advanced, moving in a transverse arcuate path between the tufts of the dry bristles of one side row to be wiped clean, then between the tufts of wetted bristles to draw off fluid therefrom, and finally, between the tufts of dry bristles of the other side row to wipe excess fluid from said brushes prior to engagement of said brushes with the bank contacts aligned therewith.

2. Cleaning means according to claim 1 in which the rows of tufts of bristles extend angularly upward and the same are largely above the level of the wick in the body, whereby the row of tufts of wetted bristles receives fluid mainly by capillary attraction.

3. Cleaning means according to claim 1 in which each constricted opening, from its end adjacent the bristle tuft with which it is in register, conically flares in size from a pinpoint opening.

4. Cleaning means according to claim 1 in which fewer rows of tufts of dry bristles are provided on the cleaning side of the row of wetted bristles than on the side where excess fluid is removed from the brushes.

5. Cleaning means according to claim 4 and further comprising:

(a) a fluid holder adapted to be fixedly mounted forwardly of the rotary switch and provided with a removable top closure enabling the holder to be replenished with fluid, and

(b) the mentioned inlet comprising a tube extending from the lower end of said holder to conduct a gravitational flow of fluid, the discharge end of said tube being connected to the applicator body to support the same and being open to the wick in the hollow of said body.

l6. Cleaning means according to claim 5 in which the tube is provided with a lateral offset and the end thereof connected to the applicator body being connected substantially midway of the length of the body, the fluid holder and applicator being offset laterally.

References Cited UNITED STATES PATENTS 113,923 4/1871 Poitras 401-283 X 2,281,367 4'/ 1942 Moll 401-272 2,571,320 10/1951 Waters 184-16 3,198,287 8/1965 Lyden 184-16 DANIEL BLUM, Primary Examiner 

